To see the other types of publications on this topic, follow the link: Digital correlation of images (DIC).
Journal articles on the topic 'Digital correlation of images (DIC)'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Digital correlation of images (DIC).'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Suswanto, Budi, Data Iranata, and Yanisfa Septiarsilia. "Analysis of Steel Material Characteristics using Digital Image Correlation (DIC) Method." MEDIA KOMUNIKASI TEKNIK SIPIL 30, no. 1 (2024): 95–104. http://dx.doi.org/10.14710/mkts.v30i1.59491.
Full textAbstract:
The use of steel materials in building construction opens new opportunities for sustainable development, as steel exhibits corrosion resistance, durability, and reliability in terms of strength and ductility. Digital Image Correlation (DIC) is non-contact technique in which digital images of the surface of a test object are captured using high-resolution cameras. This study conducted measurements of strain distribution on the specimen's surface using the DIC method throughout the entire tensile testing process. The study particularly focuses on examining changes in strain distribution during the melting phase and the local deformation phase leading to fracture. In this research, a comparison will be made between the load-displacement curves obtained from experimental laboratory testing and the results analyzed using the DIC method for SS400-grade steel material. Based on the results of the tensile test and DIC analysis that have been conducted, conclusions have been drawn in the research. The tensile test results of SS400 steel material with a thickness of 6 mm, 8 mm, 10 mm, and 12 mm meet the quality requirements in the tested specification standards, and the results of the force-displacement curve between the experimental test results and the DIC method obtained a minimum deviation with a value below 10%,. Therefore, it can be concluded that the DIC method exhibits a reasonably good level of accuracy, making it suitable for validating the results of experimental tests.
2
Atkinson, Devan, and Thorsten Hermann Becker. "Stereo Digital Image Correlation in MATLAB." Applied Sciences 11, no. 11 (2021): 4904. http://dx.doi.org/10.3390/app11114904.
Full textAbstract:
Digital Image Correlation (DIC) has found widespread use in measuring full-field displacements and deformations experienced by a body from images captured of it. Stereo-DIC has received significantly more attention than two-dimensional (2D) DIC since it can account for out-of-plane displacements. Although many aspects of Stereo-DIC that are shared in common with 2D DIC are well documented, there is a lack of resources that cover the theory of Stereo-DIC. Furthermore, publications which do detail aspects of the theory do not detail its implementation in practice. This literature gap makes it difficult for newcomers to the field of DIC to gain a deep understanding of the Stereo-DIC process, although this knowledge is necessary to contribute to the development of the field by either furthering its capabilities or adapting it for novel applications. This gap in literature acts as a barrier thereby limiting the development rate of Stereo-DIC. This paper attempts to address this by presenting the theory of a subset-based Stereo-DIC framework that is predominantly consistent with the current state-of-the-art. The framework is implemented in practice as a 202 line MATLAB code. Validation of the framework shows that it performs on par with well-established Stereo-DIC algorithms, indicating it is sufficiently reliable for practical use. Although the framework is designed to serve as an educational resource, its modularity and validation make it attractive as a means to further the capabilities of DIC.
3
Zhang, Rui. "Elastic Parameters Measurement of Rubber by Digital Image Correlation." Applied Mechanics and Materials 444-445 (October 2013): 1532–35. http://dx.doi.org/10.4028/www.scientific.net/amm.444-445.1532.
Full textAbstract:
Application of Digital image correlation method (DIC) to measure the elastic modulus and Poisson ratio of rubber under compression is investigated in this paper. Surface images of the rubber surface subjected to various loading were captured using a CCD camera. DIC is subsequently used to obtain displacement field by correlating the images captured before and after deformation, and then the average compression strain is obtained by fitting the displacement using linear plane. The slope of each set of applied stress versus measured strain data is calculated by least-squares linear regression. The elastic modulus and Poisson ratio obtained from DIC, are compared to that determined from the dial gauge, which shows that they are in good accordance with existing data. Experimental results clearly show that DIC is suitable for accurate measurement the elastic modulus of rubber.
4
Uzun, Fatih, and Alexander M. Korsunsky. "Digital Image Correlation for Elastic Strain Evaluation during Focused Ion Beam Ring-Core Milling." Journal of Manufacturing and Materials Processing 8, no. 4 (2024): 144. http://dx.doi.org/10.3390/jmmp8040144.
Full textAbstract:
The utilization of the focused ion beam digital image correlation (FIB-DIC) technique for measuring in-plane displacements and the employment of the height digital image correlation (hDIC) technique as two-step DIC for determining both in-plane and out-of-plane displacements within the region of interest are detailed in this paper. Consideration is given to the microscopy data’s measurement scale and resolution to confirming the capability of both techniques to conduct micro-scale correlations with nano-scale sensitivity, thereby making it suitable for investigating the residual elastic strains formed due to processing. The sequential correlation procedure of the FIB-DIC technique has been optimized to achieve a balance between accuracy and performance for correlating sequential scanning electron microscope images. Conversely, the hDIC technique prioritizes the accurate correlation of SEM images directly with the reference state without a sequential procedure and offers optimal computational performance through advanced parallel computing tools, particularly suited for correlating profilometry data related to large-scale displacements. In this study, the algorithm of the hDIC technique is applied as two-step DIC to evaluate the elastic strain relaxation on the surface of a ring-core drilled using focused ion beam. Both techniques are utilized to correlate the same scanning electron microscope images collected during the monitoring of the ring drilling process. A comparison of the correlation results of both techniques is undertaken regarding the quantification of the near-surface residual elastic strains, with the analysis conducted to discern the superior accuracy of the hDIC algorithm. Furthermore, the distinctions between the two techniques are delineated and discussed.
5
Jarrett, Steven R., Thinh Q. Thai, Lindsey J. Rowley, Weston D. Craig, and Ryan B. Berke. "The Effect of Bit Depth on High-Temperature Digital Image Correlation Measurements." Journal of Sensors 2022 (June 2, 2022): 1–19. http://dx.doi.org/10.1155/2022/6554128.
Full textAbstract:
Digital Image Correlation (DIC) is a camera-based method of measuring displacement and strain. High-temperature DIC is challenging due to light emitted from the sample which can saturate the image. This effect can be mitigated using optical bandpass filters, but the maximum sample temperature range of DIC remains dependent on the camera and camera settings. Among camera settings, bit depth, also referred to as color depth or number of bits, has received insufficient attention in high-temperature DIC literature. In this work, the effect of bit depth on DIC measurements is investigated both analytically and experimentally. It is shown that if image noise is sufficiently low, then increasing bit depth reduces DIC random error. A new metric, the effective number of bits, is presented to determine the appropriate number of bits for DIC images. Using increased bit depth, reduced exposure time, and low-noise images, the maximum sample temperature for DIC measurements was shown to increase without negatively impacting random error.
6
Bailey, Daniel. "Using Digital Image Correlation to Measure Full Field Strain." AM&P Technical Articles 172, no. 10 (2014): 23–24. http://dx.doi.org/10.31399/asm.amp.2014-10.p023.
Full textAbstract:
Abstract Existing strain measurement techniques do not offer enough information about how failures occur, so alternative methods are needed. One technique involves using digital image correlation (DIC) to measure full field strain over the entire material surface. DIC works by capturing a series of images throughout a test and analyzing them afterwards.
7
Dan, Xizuo, Junrui Li, Qihan Zhao, Fangyuan Sun, Yonghong Wang, and Lianxiang Yang. "A Cross-Dichroic-Prism-Based Multi-Perspective Digital Image Correlation System." Applied Sciences 9, no. 4 (2019): 673. http://dx.doi.org/10.3390/app9040673.
Full textAbstract:
A robust three-perspective digital image correlation (DIC) system based on a cross dichroic prism and single three charge-coupled device (3CCD) color cameras is proposed in this study. Images from three different perspectives are captured by a 3CCD camera using the cross dichroic prism and two planar mirrors. These images are then separated by different CCD channels to perform correlation calculation with an existing multi-camera DIC algorithm. The proposed system is considerably more compact than the conventional multi-camera DIC system. In addition, the proposed system has no loss of spatial resolution compared with the traditional single-camera DIC system. The principle and experimental setup of the proposed system is described in detail, and a series of tests is performed to validate the system. Experimental results show that the proposed system performs well in displacement, morphology, and strain measurement.
8
Chen, Jiangping, and Weijun Tao. "Gradient-Based Automatic Exposure Control for Digital Image Correlation." Sustainability 15, no. 2 (2023): 1149. http://dx.doi.org/10.3390/su15021149.
Full textAbstract:
Digital image correlation (DIC) is widely used in material experiments such as ores; the quality of a speckle image directly affects the accuracy of the DIC calculation. This study aims to acquire high-quality speckle pattern images and improve the calculation accuracy and stability. A gradient-based image quality metric was selected to evaluate the image quality, and its validity was verified by a rigid body experiment and a numerical experiment. Based on the maximum image quality metric, an automatic exposure control algorithm and the control procedure were proposed to obtain the optimal exposure time. Finally, nine sets of images with different poses and illuminations were captured, and displacement and strain fields were calculated at the fixed exposure time and the optimized exposure time. The results of the rigid-body motion experiment show that the calculated data at the optimized exposure time is smoother and less noisy, and the error is smaller, which verifies the effectiveness of the exposure control procedure and its algorithm and improves the accuracy and stability of DIC calculation.
9
Giancane, Simone, Riccardo Nobile, Francesco W. Panella, and Vito Dattoma. "Damage Evolution of Composite Laminates with Digital Image Correlation." Key Engineering Materials 452-453 (November 2010): 377–80. http://dx.doi.org/10.4028/www.scientific.net/kem.452-453.377.
Full textAbstract:
DIC (Digital Image Correlation) based methodology gives full field measure of the displacement using a well defined algorithm for matching the images of loaded and load free component, so that displacement in a plane can be evaluated for a certain number of grid reference points on the analysed surface. In this work, the authors present an application of DIC technique to analyse fatigue damage phenomena in two notched GFRC laminates under tensile load. Damage analysis based on optical DIC technique has been performed to detect the damaged areas on the specimen surface. The damage evolution and failure mechanism has been followed monitoring two parameters: the local hysteresis area of stress-strain cycles, the local stiffness variation.
10
Lim, Chhoung, Yeongseok Jeong, Suchart Limkantanyu, and Minho Kwon. "Strain Measuring of Composite Grid Using Digital Image Correlation." Advances in Materials Science and Engineering 2022 (April 14, 2022): 1–12. http://dx.doi.org/10.1155/2022/6041887.
Full textAbstract:
Digital Image Correlation (DIC) is a new advanced technique for measuring the deformation of a specimen using high-resolution images. It has been used by numerous researchers since it can measure the deformation of specimens without interference because it is contactless. Moreover, the DIC technique can be applied to any materials to which normal measuring equipment is difficult to attach such as Fiber-Reinforced Polymer (FRP) grid in this paper, undulated and small surfaces. The DIC technique is easy to set up and provides reliable results compared to conventional equipment like a strain gauge. Although it is good, its associated equipment is too expensive to be readily affordable. Hence, this paper uses an open-source DIC program called Ncorr that works in MATLAB to analyze deformations of six FRP grids from direct tensile tests by comparing their results to the results from a strain gauge. Young’s modulus—calculated from ASTM 3039, ACI 440-3R-04, and regression analysis—of each specimen will be used for comparison. The results show that the difference between Young’s modulus from DIC and strain gauge is <5% if the stress–strain graph of data from the strain gauge is perfectly linear without straying.
11
Mousa, Mohammed Abbas, Mustafasanie M. Yussof, Lateef N. Assi, and SeyedAli Ghahari. "A Pre-Process Enhanced Digital Image Correlation Approach for Smart Structure Monitoring." Infrastructures 7, no. 10 (2022): 141. http://dx.doi.org/10.3390/infrastructures7100141.
Full textAbstract:
This research provides a practical guideline for Digital Image Correlation (DIC) data variations minimization in structural engineering through simple image processing techniques. The main objective of this research is to investigate the Pixel Averaging (P.A.) effect on the differential strain Diff(εx) variations. Three concrete arches were tested with three-point bending using the DIC technique for strain measurements. The measured strains are obtained through two virtual horizontal extensometers in the middle of each arch. The Diff(εx) was selected to avoid other 2D-DIC issues, such as the sample-camera out-of-plane movement. Three image cases, namely, one, ten, and twenty averaged images, were used for DIC analysis of each arch. The conditions of each image case are assessed by computing the Diff(εx) variance and the linear least square criterion (R2) between the two extensometers. The second objective is to examine the speckles’ dilation effects on the speckle pattern density and surface component quality utilizing the Image Erode (I.E.) technique. The (P.A.) technique provided consistent differential strain Diff(εx) values with a variance reduction of up to (90%) when averaged images were used. The (R2) has considerably increased (from 0.46, 0.66, 0.91 to 0.90, 0.96, 0.99), respectively, for the three samples. Moreover, the (I.E.) technique provided qualitatively denser speckles with a highly consistent DIC surface component.
12
Lee, Junhwa, Eun Kim, Seongwoo Gwon, Soojin Cho, and Sung-Han Sim. "Uniaxial Static Stress Estimation for Concrete Structures Using Digital Image Correlation." Sensors 19, no. 2 (2019): 319. http://dx.doi.org/10.3390/s19020319.
Full textAbstract:
This paper proposes a static stress estimation method for concrete structures, using the stress relaxation method (SRM) in conjunction with digital image correlation (DIC). The proposed method initially requires a small hole to be drilled in the concrete surface to induce stress relaxation around the hole and, consequently, a displacement field. DIC measures this displacement field by comparing digital images taken before and after the hole-drilling. The stress level in the concrete structure is then determined by solving an optimization problem, designed to minimize the difference between the displacement fields from DIC and the one from a numerical model. Compared to the pointwise measurements by strain gauges, the full-field displacement obtained by DIC provides a larger amount of data, leading to a more accurate estimation. Our theoretical results were experimentally validated using concrete specimens, demonstrating the efficacy of the proposed method.
13
Atkinson, Devan, and Thorsten Becker. "A 117 Line 2D Digital Image Correlation Code Written in MATLAB." Remote Sensing 12, no. 18 (2020): 2906. http://dx.doi.org/10.3390/rs12182906.
Full textAbstract:
Digital Image Correlation (DIC) has become a popular tool in many fields to determine the displacements and deformations experienced by an object from images captured of the object. Although there are several publications which explain DIC in its entirety while still catering to newcomers to the concept, these publications neglect to discuss how the theory presented is implemented in practice. This gap in literature, which this paper aims to address, makes it difficult to gain a working knowledge of DIC, which is necessary in order to contribute towards its development. The paper attempts to address this by presenting the theory of a 2D, subset-based DIC framework that is predominantly consistent with state-of-the-art techniques, and discussing its implementation as a modular MATLAB code. The correlation aspect of this code is validated, showing that it performs on par with well-established DIC algorithms and thus is sufficiently reliable for practical use. This paper, therefore, serves as an educational resource to bridge the gap between the theory of DIC and its practical implementation. Furthermore, although the code is designed as an educational resource, its validation combined with its modularity makes it attractive as a starting point to develop the capabilities of DIC.
14
Zouabi, Haythem, Madalina Calamaz, Vincent Wagner, Olivier Cahuc, and Gilles Dessein. "Kinematic Fields Measurement during Orthogonal Cutting Using Digital Images Correlation: A Review." Journal of Manufacturing and Materials Processing 5, no. 1 (2021): 7. http://dx.doi.org/10.3390/jmmp5010007.
Full textAbstract:
Understanding the mechanism of chip formation during orthogonal cutting requires a local measurement of the displacement and strain fields in the cutting zone. These measurements can then be used in order to enhance/validate numerical simulation of metal cutting or calibrate material behavior laws for a better prediction of the thermomechanical loads inside the cutting zone. Particle tracking to identify the strain localization that is exhibited in the Adiabatic Shear Band (ASB) is a challenging task. These local measurements can be determined by images post-processing while using the Digital Image Correlation (DIC) technique or analytical models using streamline models or by micro grid analysis. Recently, the use of the DIC technique is widely increased. Texture quality has been shown to be an important factor. Various techniques of surface preparation are then discussed and classified in terms of the created pattern size. Tools for texture analysis are presented. The technique suitability for the kinematic fields measurement while using the DIC technique during machining is discussed. Various optical systems of the literature employed in the context of kinematic fields measurement during machining are discussed in this paper. The recent advances on the design of optical systems are given. Finally, the results of kinematic fields measurement during machining metallic alloys are analyzed.
15
Zouabi, Haythem, Madalina Calamaz, Vincent Wagner, Olivier Cahuc, and Gilles Dessein. "Kinematic Fields Measurement during Orthogonal Cutting Using Digital Images Correlation: A Review." Journal of Manufacturing and Materials Processing 5, no. 1 (2021): 7. http://dx.doi.org/10.3390/jmmp5010007.
Full textAbstract:
Understanding the mechanism of chip formation during orthogonal cutting requires a local measurement of the displacement and strain fields in the cutting zone. These measurements can then be used in order to enhance/validate numerical simulation of metal cutting or calibrate material behavior laws for a better prediction of the thermomechanical loads inside the cutting zone. Particle tracking to identify the strain localization that is exhibited in the Adiabatic Shear Band (ASB) is a challenging task. These local measurements can be determined by images post-processing while using the Digital Image Correlation (DIC) technique or analytical models using streamline models or by micro grid analysis. Recently, the use of the DIC technique is widely increased. Texture quality has been shown to be an important factor. Various techniques of surface preparation are then discussed and classified in terms of the created pattern size. Tools for texture analysis are presented. The technique suitability for the kinematic fields measurement while using the DIC technique during machining is discussed. Various optical systems of the literature employed in the context of kinematic fields measurement during machining are discussed in this paper. The recent advances on the design of optical systems are given. Finally, the results of kinematic fields measurement during machining metallic alloys are analyzed.
16
Zouabi, Haythem, Madalina Calamaz, Vincent Wagner, Olivier Cahuc, and Gilles Dessein. "Kinematic Fields Measurement during Orthogonal Cutting Using Digital Images Correlation: A Review." Journal of Manufacturing and Materials Processing (JMMP) 5, Optimization and Simulation of Solid State Manufacturing Processes (2021): 1:7. https://doi.org/10.3390/jmmp5010007.
Full textAbstract:
Understanding the mechanism of chip formation during orthogonal cutting requires a local measurement of the displacement and strain fields in the cutting zone. These measurements can then be used in order to enhance/validate numerical simulation of metal cutting or calibrate material behavior laws for a better prediction of the thermomechanical loads inside the cutting zone. Particle tracking to identify the strain localization that is exhibited in the Adiabatic Shear Band (ASB) is a challenging task. These local measurements can be determined by images post-processing while using the Digital Image Correlation (DIC) technique or analytical models using streamline models or by microgrid analysis. Recently,the use of the DIC technique is widely increased. Texture quality has been shown to be an important factor. Various techniques of surface preparation are then discussed and classified in terms of the created pattern size. Tools for texture analysis are presented. The technique suitability for the kinematic fields measurement while using the DIC technique during machining is discussed. Various optical systems of the literature employed in the context of kinematic fields measurement during machining are discussed in this paper. The recent advances on the design of optical systems are given. Finally, the results of kinematic fields measurement during machining metallic alloys are analyzed.
17
Zhang, Chuang, Cong Liu, and Zhihong Xu. "High-Accuracy Three-Dimensional Deformation Measurement System Based on Fringe Projection and Speckle Correlation." Sensors 23, no. 2 (2023): 680. http://dx.doi.org/10.3390/s23020680.
Full textAbstract:
Fringe projection profilometry (FPP) and digital image correlation (DIC) are widely applied in three-dimensional (3D) measurements. The combination of DIC and FPP can effectively overcome their respective shortcomings. However, the speckle on the surface of an object seriously affects the quality and modulation of fringe images captured by cameras, which will lead to non-negligible errors in the measurement results. In this paper, we propose a fringe image extraction method based on deep learning technology, which transforms speckle-embedded fringe images into speckle-free fringe images. The principle of the proposed method, 3D coordinate calculation, and deformation measurements are introduced. Compared with the traditional 3D-DIC method, the experimental results show that this method is effective and precise.
18
Koga, Norimitsu, and Osamu Umezawa. "Visualization of Strain Distribution on Deformed Steels Using Digital Image Correlation Method." Key Engineering Materials 741 (June 2017): 138–43. http://dx.doi.org/10.4028/www.scientific.net/kem.741.138.
Full textAbstract:
Digital image correlation (DIC) method is a convenient strain analysis method calculating strain from the difference of images between before and after deformation and shows an advantage to apply to any deformation mode or materials as long as significant contrast. We reviewed basic principles of DIC method and then demonstrated strain distribution in tensile deformed ferritic steel and cyclic deformed tempered martensitic steel. Strain distribution in tensile deformed ferritic steel becomes inhomogeneous with lowering temperature due to restriction of slip systems at low temperature. Strain distribution around a fatigue crack in cyclic deformed tempered martensitic steel was visualized by DIC analysis for replica film and strain concentrated on crack tip same as previous report in DIC analysis for specimen surface, which suggests that strain distribution obtained from replica film has an enough reliability. From these results, it can be concluded that DIC analysis is effective method to investigate local deformation and relation between local deformation and fracture behavior in metal materials.
19
Khoo, Sze-Wei, Saravanan Karuppanan, and Ching-Seong Tan. "A Review of Surface Deformation and Strain Measurement Using Two-Dimensional Digital Image Correlation." Metrology and Measurement Systems 23, no. 3 (2016): 461–80. http://dx.doi.org/10.1515/mms-2016-0028.
Full textAbstract:
Abstract Among the full-field optical measurement methods, the Digital Image Correlation (DIC) is one of the techniques which has been given particular attention. Technically, the DIC technique refers to a non-contact strain measurement method that mathematically compares the grey intensity changes of the images captured at two different states: before and after deformation. The measurement can be performed by numerically calculating the displacement of speckles which are deposited on the top of object’s surface. In this paper, the Two-Dimensional Digital Image Correlation (2D-DIC) is presented and its fundamental concepts are discussed. Next, the development of the 2D-DIC algorithms in the past 33 years is reviewed systematically. The improvement of 2DDIC algorithms is presented with respect to two distinct aspects: their computation efficiency and measurement accuracy. Furthermore, analysis of the 2D-DIC accuracy is included, followed by a review of the DIC applications for two-dimensional measurements.
20
Zhu, Kaiyu, and Bing Pan. "Panoramic/Dual-Surface Digital Image Correlation Measurement Using a Single Camera." Sensors 22, no. 9 (2022): 3266. http://dx.doi.org/10.3390/s22093266.
Full textAbstract:
We propose a cost-effective and simple-to-implement mirror-assisted single-camera panoramic digital image correlation (DIC) method for panoramic/dual-surface profile and deformation measurement. Specifically, two planar mirrors and a single camera attached with a four-mirror adapter are used to capture stereo images of the front and rear surfaces of a test object. These stereo images can be processed by regular stereo-DIC to retrieve shape and kinematics fields of each surface. Further, with the speckle patterns prefabricated on the mirrors, reflection transformation matrices are obtained and applied to transform all reconstructed surfaces into a common world coordinate system. As such, panoramic/dual-surface shape and deformation measurements can be realized. For validation, a high-resolution smartphone camera and an industrial camera were, respectively, used to construct mirror-assisted single-camera panoramic DIC systems. Real experiments, including panoramic shape measurement of an aluminum cylinder, dual-surface shape measurement of an aluminum plate and uniaxial tensile tests of aluminum sheet specimens, were performed, confirming the feasibility and accuracy of the method. Since only a single camera and a few auxiliary reflective mirrors are required, the proposed method provides a cost-effective and convenient way for taking panoramic/dual-surface shape and deformation measurements of regular-sized cylindrical and bar samples.
21
Zhu, Kaiyu, and Bing Pan. "Panoramic/Dual-Surface Digital Image Correlation Measurement Using a Single Camera." Sensors 22, no. 9 (2022): 3266. http://dx.doi.org/10.3390/s22093266.
Full textAbstract:
We propose a cost-effective and simple-to-implement mirror-assisted single-camera panoramic digital image correlation (DIC) method for panoramic/dual-surface profile and deformation measurement. Specifically, two planar mirrors and a single camera attached with a four-mirror adapter are used to capture stereo images of the front and rear surfaces of a test object. These stereo images can be processed by regular stereo-DIC to retrieve shape and kinematics fields of each surface. Further, with the speckle patterns prefabricated on the mirrors, reflection transformation matrices are obtained and applied to transform all reconstructed surfaces into a common world coordinate system. As such, panoramic/dual-surface shape and deformation measurements can be realized. For validation, a high-resolution smartphone camera and an industrial camera were, respectively, used to construct mirror-assisted single-camera panoramic DIC systems. Real experiments, including panoramic shape measurement of an aluminum cylinder, dual-surface shape measurement of an aluminum plate and uniaxial tensile tests of aluminum sheet specimens, were performed, confirming the feasibility and accuracy of the method. Since only a single camera and a few auxiliary reflective mirrors are required, the proposed method provides a cost-effective and convenient way for taking panoramic/dual-surface shape and deformation measurements of regular-sized cylindrical and bar samples.
22
Crammond, G., S. W. Boyd, and Janice M. Dulieu-Barton. "Speckle Pattern Characterisation for High Resolution Digital Image Correlation." Applied Mechanics and Materials 70 (August 2011): 261–66. http://dx.doi.org/10.4028/www.scientific.net/amm.70.261.
Full textAbstract:
Digital image correlation (DIC) is an optical technique for full field deformation measurement. The spatial resolution and precision of the measurements are limited by the number of pixels within the image. The use of magnifying optics provides greater spatial resolution images, enabling smaller displacements to be observed with greater accuracy. Increasing the magnification of an image significantly changes the appearance of the non-periodic, stochastic speckle pattern which provides the grey scale contrast necessary for the image correlation method. In the paper a methodology is developed to evaluate the properties of different speckle pattern types under a range of resolutions up to 705 pixel / mm. Numerical deformation of the patterns is also undertaken to evaluate how the changes in the pattern properties affect the accuracy of the DIC measurements.
23
SANTOS, A. H. A., R. L. S. PITANGUEIRA, G. O. RIBEIRO, and E. V. M. CARRASCO. "Concrete modulus of elasticity assessment using digital image correlation." Revista IBRACON de Estruturas e Materiais 9, no. 4 (2016): 587–94. http://dx.doi.org/10.1590/s1983-41952016000400007.
Full textAbstract:
Abstract This paper presents the use of the technique of digital image correlation for obtaining the elasticity modulus of concrete. The proposed system uses a USB microscope that captures images at a rate of five frames per second. The stored data are correlated with the applied loads, and a stress-strain curve is generated to determine the concrete compressive modulus of elasticity. Two different concretes were produced and tested using the proposed system. The results were compared with the results obtained using a traditional strain gauge. It was observed a difference in the range of 4% between the two methods, wherein this difference depends on some parameters in the case of the DIC results, as focal length and a video capture resolution, indicating that DIC technique can be used to obtain mechanical properties of concrete.
24
Grant, B. M. B., H. J. Stone, P. J. Withers, and M. Preuss. "High-temperature strain field measurement using digital image correlation." Journal of Strain Analysis for Engineering Design 44, no. 4 (2009): 263–71. http://dx.doi.org/10.1243/03093247jsa478.
Full textAbstract:
A method is presented for obtaining good images of sample surfaces at high temperatures, suitable for strain measurement, by digital image correlation (DIC) without the use of surface markers or speckles. This is accomplished by suppressing black-body radiation through the use of filters and blue illumination. Using only relatively low levels of illumination the method is demonstrated to be capable of providing accurate DIC measurements up to 1100 °C, and the potential to monitor strains to 1400 °C is identified. The capability of the method is demonstrated by measuring the Young's modulus and coefficient of thermal expansion of a nickel-base superalloy at temperatures from ambient to 1000 °C; two parameters that are well established in the literature and that require high strain sensitivity for their reliable determination.
25
Belloni, V., R. Ravanelli, A. Nascetti, M. Di Rita, D. Mattei, and M. Crespi. "DIGITAL IMAGE CORRELATION FROM COMMERCIAL TO FOS SOFTWARE: A MATURE TECHNIQUE FOR FULL-FIELD DISPLACEMENT MEASUREMENTS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-2 (May 30, 2018): 91–95. http://dx.doi.org/10.5194/isprs-archives-xlii-2-91-2018.
Full textAbstract:
In the last few decades, there has been a growing interest in studying non-contact methods for full-field displacement and strain measurement. Among such techniques, Digital Image Correlation (DIC) has received particular attention, thanks to its ability to provide these information by comparing digital images of a sample surface before and after deformation. The method is now commonly adopted in the field of civil, mechanical and aerospace engineering and different companies and some research groups implemented 2D and 3D DIC software. In this work a review on DIC software status is given at first. Moreover, a free and open source 2D DIC software is presented, named py2DIC and developed in Python at the Geodesy and Geomatics Division of DICEA of the University of Rome “La Sapienza”; its potentialities were evaluated by processing the images captured during tensile tests performed in the Structural Engineering Lab of the University of Rome “La Sapienza” and comparing them to those obtained using the commercial software Vic-2D developed by Correlated Solutions Inc, USA. The agreement of these results at one hundredth of millimetre level demonstrate the possibility to use this open source software as a valuable 2D DIC tool to measure full-field displacements on the investigated sample surface.
26
Ma, Chang, Zhoumo Zeng, Hui Zhang, and Xiaobo Rui. "A Correction Method for Heat Wave Distortion in Digital Image Correlation Measurements Based on Background-Oriented Schlieren." Applied Sciences 9, no. 18 (2019): 3851. http://dx.doi.org/10.3390/app9183851.
Full textAbstract:
Digital image correlation (DIC) is a kind of displacement and strain measurement technique. It can realize non-contact and full-field measurement and is widely used in the testing and research of mechanical properties of materials at high temperatures. However, many factors affect measurement accuracy. As the high temperature environment is complex, the impact of heat waves on DIC is the most significant factor. In order to correct the disturbance in DIC measurement caused by heat waves, this paper proposes a method based on the background-oriented schlieren (BOS) technique. The spot pattern on the surface of a specimen in digital image correlation can be used as the background in the background-oriented schlieren technique. The BOS technique can measure the distortion information of the images caused by heat flow field. The specimen images taken through the heat waves can be corrected using the distortion information. Besides, the characteristics of distortions due to heat waves are also studied in this paper. The experiment results verify that the proposed method can effectively eliminate heat wave disturbances in DIC measurements.
27
Fíla, Tomáš, Petr Zlámal, Jan Falta, et al. "Testing of Auxetic Materials Using Hopkinson Bar and Digital Image Correlation." EPJ Web of Conferences 183 (2018): 02045. http://dx.doi.org/10.1051/epjconf/201818302045.
Full textAbstract:
In this paper, a split Hopkinson pressure bar (SHPB) was used for impact loading of an auxetic lattice (structure with negative Poisson’s ratio) at a given strain-rate. High strength aluminum and polymethyl methacrylate bars instrumented with foil strain-gauges were used for compression of an additively manufactured missing-rib auxetic lattice. All experiments were observed using a high-speed camera with frame-rate set to approx. 135.000 fps. High-speed images were synchronized with the strain-gauge records. Dynamic equilibrium in the specimen was analyzed and optimized pulse-shaping was introduced in the selected experiments. Longitudinal and lateral in-plane displacements and strains were evaluated using digital image correlation (DIC) technique. DIC results were compared with results obtained from strain-gauges and were found to be in good agreement. Using DIC, it was possible to analyze in-plane strain distribution in the specimens and to evaluate strain dependent Poisson’s ratio of the auxetic structure.
28
Hermle, Doris, Markus Keuschnig, Michael Krautblatter, and Valentin Tertius Bickel. "Systematic Quantification and Assessment of Digital Image Correlation Performance for Landslide Monitoring." Geosciences 13, no. 12 (2023): 371. http://dx.doi.org/10.3390/geosciences13120371.
Full textAbstract:
Accurate and reliable analyses of high-alpine landslide displacement magnitudes and rates are key requirements for current and future alpine early warnings. It has been proved that high spatiotemporal-resolution remote sensing data combined with digital image correlation (DIC) algorithms can accurately monitor ground displacements. DIC algorithms still rely on significant amounts of expert input; there is neither a general mathematical description of type and spatiotemporal resolution of input data nor DIC parameters required for successful landslide detection, accurate characterisation of displacement magnitude and rate, and overall error estimation. This work provides generic formulas estimating appropriate DIC input parameters, drastically reducing the time required for manual input parameter optimisation. We employed the open-source code DIC-FFT using optical remote sensing data acquired between 2014 and 2020 for two landslides in Switzerland to qualitatively and quantitatively show which spatial resolution is required to recognise slope displacements, from satellite images to aerial orthophotos, and how the spatial resolution affects the accuracy of the calculated displacement magnitude and rate. We verified our results by manually tracing geomorphic markers in orthophotos. Here, we show a first generic approach for designing and optimising future remote sensing-based landslide monitoring campaigns to support time-critical applications like early warning systems.
29
Sjögren, Torsten, Per Eric Persson, and Peter Vomacka. "Analysing the Deformation Behaviour of Compacted Graphite Cast Irons Using Digital Image Correlation Techniques." Key Engineering Materials 457 (December 2010): 470–75. http://dx.doi.org/10.4028/www.scientific.net/kem.457.470.
Full textAbstract:
During the last years the use of digital image correlation techniques (DIC) has become wide spread within different areas of research. One area in which these techniques are used is in the analysis of deformation of engineering materials. By the analysis of a set of successive images taken during a tensile test DIC makes it possible to determine how the deformation is localized. The observed local strains are often several times higher than the global strain measured by standard strain gauges. In this study, a set of compacted graphite cast irons (CGI) with different ratios of pearlite to ferrite have been examined by the use of DIC. In contrast to the normal use of DIC, where a pattern is sprayed on the tensile test sample as a reference for the determination of deformation taking place between successive images, the materials natural microstructural pattern has been used in this study. The use of the natural microstructural pattern makes it possible to study how the macroscopic deformation is accommodated within the different phases in the CGI studied. It is shown that the graphite phase accommodates a large portion of the strain and that the soft ferrite is strained more than the stronger, less ductile pearlite. The local strain of the observed area might be up to ten times higher than the global strain measured. The use of DIC improves the understanding of the deformation behaviour of compacted graphite cast irons and will be a useful tool when validating future finite element analyses of the micro-mechanical properties of cast irons.
30
Tewari, Kavita, and R. K. Kulkarni. "Locating Cracks in 1050 Aluminium Alloy by Digital Image Correlation." SAMRIDDHI : A Journal of Physical Sciences, Engineering and Technology 13, no. 02 (2021): 104–8. http://dx.doi.org/10.18090/samriddhi.v13i02.8.
Full textAbstract:
In this paper deformation of commercial 1050 grade aluminum alloy is studied by digital image correlation (DIC) technique using open-source software, Ncorr. For this purpose, samples of aluminum alloy were subjected to uniaxial deformation under a scanning electron microscope (SEM) till the initiation of crack. Intermittently images were captured during deformation and by using DIC technique, variations in the microstructure of the deformed samples were identified in terms of displacement. Using these displacements, normal strains Exx, Eyy, and Exy shear strain were estimated to subpixel accuracy. By superimposing the region of crack and distribution of strains in the microstructures, it was possible to show that near the crack, strains not only attain high values but also show large fluctuations. Various aspects relating to the nature of strain distribution are discussed in the paper.
31
Guo, Xiang, Yu Long Li, Tao Suo, Zhong Bin Tang, and Ying Gang Miao. "Stationary Wavelet Transform Based on De-Noising of Digital Image Correlation in the Investigation on the Impact Response." Key Engineering Materials 715 (September 2016): 128–32. http://dx.doi.org/10.4028/www.scientific.net/kem.715.128.
Full textAbstract:
This paper proposes a method for removing image noise form images captured during the impact experiment for the DIC measurement. This paper focuses on estimating the light noise from captured images taken by the deformation during the impact. An image enhanced method based on stationary wavelet transform was employed to improve the stability and accuracy in the DIC measurement. The proposed method was investigated under the impact experiment. The experiment results show that overall the stability and accuracy of the proposed method was improved.
32
Kumar V, Vinay, and Sireesh Saride. "Use of Digital Image Correlation for the Evaluation of Flexural Fatigue Behavior of Asphalt Beams with Geosynthetic Interlayers." Transportation Research Record: Journal of the Transportation Research Board 2631, no. 1 (2017): 55–64. http://dx.doi.org/10.3141/2631-06.
Full textAbstract:
In this study, the flexural fatigue performance of two-layer asphalt beams with and without geosynthetic interlayers was evaluated with a digital image correlation (DIC) technique. A field scenario was simulated by considering an old, destressed pavement as the bottom layer with a compacted bituminous mix as an overlay. An appropriate tack coat and geosynthetic interlayer were at the interface. The digital images were recorded at a specific interval of load cycles during a repeated load four-point bending test. The displacement fields obtained from the digital images were analyzed so that the crack width, crack height, and tensile strains could be obtained and the crack initiation and propagation phenomena studied. The deformation data obtained from the DIC analysis were validated with the vertical deformations measured through linear variable differential transformers. The DIC results correlated very well with the measured data. The DIC data indicated that the tensile strains were as high as 4.75% at the crack tip in the control specimen compared with 1.42% in a polyester grid interlayered specimen at the failure of the corresponding specimens. With the inclusion of interlayers, the fatigue performance of the two-layer asphalt beam specimens improved by about 39, 12, and 1.7 times for Specimens I1, I2, and I3, respectively.
33
Zhang, F. G., O. Castelnau, M. Bornert, J. Petit, J. B. Marijon, and E. Plancher. "Determination of deviatoric elastic strain and lattice orientation by applying digital image correlation to Laue microdiffraction images: the enhanced Laue-DIC method." Journal of Applied Crystallography 48, no. 6 (2015): 1805–17. http://dx.doi.org/10.1107/s1600576715018397.
Full textAbstract:
A new method of determining the deviatoric elastic strain and lattice orientation from Laue microdiffraction images is presented. Standard data treatment methods can suffer from the difficulty of precisely pinpointing the positions of diffraction peaks on two-dimensional Laue images. In a previous article, digital image correlation (DIC) was introduced for the treatment of Laue images, leading to the so-called Laue-DIC method. This performed better than the standard method in terms of the deviatoric elastic strain increment and relative rotation from one lattice to another, particularly when the shape of the Laue spots departs from regular ellipsoids. The present work intends to push forward the Laue-DIC method, aiming to determine the deviatoric elastic strain and lattice orientation, as well as the calibration parameters. The performance of this new method, named enhanced Laue-DIC, is assessed by modeling the spot displacements and accounting for random fluctuations relevant for typical experimental conditions. When the enhanced Laue-DIC method is applied to the case of anin situdeformed Si crystal, the obtained standard deviation of local stress is of the order of 1–2 MPa, while the calibration parameters are optimized to high accuracy.
34
Shao, Xinxing, Jingye Qu, and Wenwu Chen. "Single-Camera Three-Dimensional Digital Image Correlation with Enhanced Accuracy Based on Four-View Imaging." Materials 16, no. 7 (2023): 2726. http://dx.doi.org/10.3390/ma16072726.
Full textAbstract:
Owing to the advantages of cost-effectiveness, compactness, and the avoidance of complicated camera synchronization, single-camera three-dimensional (3D) digital image correlation (DIC) techniques have gained increasing attention for deformation measurement of materials and structures. In the traditional single-camera 3D-DIC system, the left and right view images can be recorded by a single camera using diffraction grating, a bi-prism, or a set of planar mirrors. To further improve the measurement accuracy of single-camera 3D-DIC, this paper introduces a single-camera four-view imaging technique by installing a pyramidal prism in front of the camera. The 3D reconstruction of the measured points before and after deformation is realized with eight governing equations induced by four views, and the strong geometric constraints of four views can help to improve the measurement accuracy. A static experiment, a rigid body translation experiment, and a four-point bending experiment show that the proposed single-camera 3D-DIC method can achieve higher measurement accuracy than the dual-view single-camera 3D-DIC techniques and that the single-camera 3D-DIC method has advantages in reducing both random error and systematic error.
35
Dong, Bo, Fancang Zeng, and Bing Pan. "A Simple and Practical Single-Camera Stereo-Digital Image Correlation Using a Color Camera and X-Cube Prism." Sensors 19, no. 21 (2019): 4726. http://dx.doi.org/10.3390/s19214726.
Full textAbstract:
A simple and practical full-frame single-camera stereo-digital image correlation (stereo-DIC) technique for three-dimensional (3D) shape, displacement, and deformation measurements is proposed. The technique uses a compact X-cube prism-based color separation device and a color camera to capture images of blue and red colors from different optical paths, and then extracts the surface 3D shape and deformation information of a test sample by processing the captured two sub-channel color images using regular stereo-DIC algorithm. Compared with the existing full-frame single-camera stereo-DICs, the proposed one eliminates the need for a beam splitter and two bandpass filters to capture images, and offers more simple, compact, and easy-to-use optical arrangement. This novel single-camera stereo-DIC technique was validated by a series of baseline experiments involving 3D surface reconstructions, translation tests, and full-field deformation measurements, which provide a new flexible and practical avenue for measuring surface 3D shape and deformation, particularly in microscopic and high-speed applications.
36
Huang, Wanghua, Kang Chen, Wei Wei, Jianbin Xiong, and Wenhao Liu. "Fast and Robust Digital Image Spearman's Rho Correlation for Displacement Measurement." Information Technology and Control 51, no. 4 (2022): 661–77. http://dx.doi.org/10.5755/j01.itc.51.4.30866.
Full textAbstract:
The robustness and computational efficiency of digital image correlation (DIC) are two key influencing factors for displacement field measurement applications. Especially when the speckle images are contaminated by salt-and-pepper noise, it is difficult to obtain reliable measurement results using traditional DIC methods. Digital image Spearman’s Rho Correlation (DISRC), as a new DIC technique, has certain robustness to salt-and-pepper noise, but incurs a high computational load when computing subset ranks. It is found that the DISRC can tolerate up to 15% noise level theoretically by analyzing the mean character of Spearman’s Rho. Meanwhile a fast scheme is proposed in which parallelization is adopted for precomputing subset rank and computing for displacement field to accelerate the DISRC. The simulation results indicate that the fast DISRC is about 60 times faster than the original one, and the displacement field results are almost the same between them. The DISRC not only gives as well results as zero-mean normalized cross-correlation (ZNCC) without any noise, but also can tolerate 20% noise level in simulations. A case study also verifies that the result by DISRC is better than ZNCC when contaminated by smaller amounts of noise. The conclusion is that the DISRC is a strong anti-interference DIC technique, which is very important in application under complex environment, and the fast scheme is an effective way to accelerate the DISRC.
37
Zhang, J., M. Li, C. Y. Xiong, J. Fang, and S. Yi. "Thermal deformation analysis of BGA package by digital image correlation technique." Microelectronics International 22, no. 1 (2005): 34–42. http://dx.doi.org/10.1108/13565360510575530.
Full textAbstract:
PurposeThe mismatch of the thermal expansion coefficients of the materials in multiplayer structure may induce serious stress concentrations in electronic packaging. Experimental evaluation of the thermal stresses and strains in those electronic composites is becoming significantly important for optimizing design and failure prediction of the electronic devices.Design/methodology/approachDigital image correlation (DIC) technique was utilized to obtain thermal deformation filed of a BGA package. With the help of white light to illuminate the cross section of the BGA package, the gray images were taken from the rough surface of the specimen, that offer a kid of carrier pattern for the DIC processing with statistical resemblance in gray distributions. By using the algorithm of correlation computation, the DIC searched the matching spots in a pair of those images in which the spot displacements were involved in between, to obtain the deformation fields of the package specimen caused by temperature changes.FindingsThe results show interesting strain distributions in the assembly. Both the horizontal displacement component and its normal derivative are strongly related to the arrangement of the solder joints in the bonding medium between the die and the ceramic substrate. The strain components in the middle region of the package are larger than those in the side regions where the strain relaxation may exist near the stress‐free boundaries. The shear strain components show special bands of parallel lines with identical amount over the chip‐package to sustain the shearing of the packed structure under thermal loading.Originality/valueThe DIC technique shows to be a useful tool for the thermal strain analysis of the electronic packaging devices. Not only provides it the whole field deformation of the assembly, but also maintains the surface pictures of the package without covering any fringes, which is important to compare the deformation field with the specimen surface to reveal the stain distribution related to the failure prediction of the materials.
38
Saracura, Rafael G. M., Rodrigo B. Canto, Victor Carlos Pandolfelli, Nicolas Schmitt, and François Hild. "Digital Image Correlation as a Tool for Monitoring Crack Networks on the Surface of MgO-Based Refractory Castables." Advances in Science and Technology 92 (October 2014): 242–47. http://dx.doi.org/10.4028/www.scientific.net/ast.92.242.
Full textAbstract:
This paper deals with the characterization of crack networks on the surface of refractory castable slabs, which are induced by stresses arising during the curing and drying (CD) stages. Images of the surface of castable samples placed in a house-made climatic chamber were recorded during the CD stages with a digital camera and processed by Digital Image Correlation (DIC) tomeasure the displacement field. Post-processing of DIC results were performed to estimate the length, orientation and opening of cracks in networks. The methodology is detailed and first analyses of experimental results are shown.
39
Hu, Hao, Boxing Qian, Yongqing Zhang, and Wenpan Li. "Digital Image Correlation with a Prism Camera and Its Application in Complex Deformation Measurement." Sensors 23, no. 12 (2023): 5531. http://dx.doi.org/10.3390/s23125531.
Full textAbstract:
Given the low accuracy of the traditional digital image correlation (DIC) method in complex deformation measurement, a color DIC method is proposed using a prism camera. Compared to the Bayer camera, the Prism camera can capture color images with three channels of real information. In this paper, a prism camera is used to collect color images. Relying on the rich information of three channels, the classic gray image matching algorithm is improved based on the color speckle image. Considering the change of light intensity of three channels before and after deformation, the matching algorithm merging subsets on three channels of a color image is deduced, including integer-pixel matching, sub-pixel matching, and initial value estimation of light intensity. The advantage of this method in measuring nonlinear deformation is verified by numerical simulation. Finally, it is applied to the cylinder compression experiment. This method can also be combined with stereo vision to measure complex shapes by projecting color speckle patterns.
40
Chiorean, Radu, Mircea Cristian Dudescu, Marius Pustan, and Mihail Hărdău. "V-Beam Thermal Actuator’s Performance Analysis Using Digital Image Correlation." Applied Mechanics and Materials 658 (October 2014): 173–76. http://dx.doi.org/10.4028/www.scientific.net/amm.658.173.
Full textAbstract:
This paper analyses the influence of the V-beam thermal actuator’s geometrical parameters on its mechanical behavior. Experimental measurements were performed using Digital Image Correlation (DIC), which is a gray scale value tracking algorithm that evaluates the position shift of a pixel between at least two images taken at different deformation stages. These results are compared to multi-physics simulation data obtained using Finite Element Analysis (FEA) as well as to analytical values based on the electro-thermal and thermo-mechanical presented models.
41
Take, W. Andy. "Thirty-Sixth Canadian Geotechnical Colloquium: Advances in visualization of geotechnical processes through digital image correlation." Canadian Geotechnical Journal 52, no. 9 (2015): 1199–220. http://dx.doi.org/10.1139/cgj-2014-0080.
Full textAbstract:
Digital image correlation (DIC) is an image-processing technique that calculates fields of incremental displacement by comparing two digital images and locating numerous small regions in both images to high subpixel accuracy. This technique is particularly well suited to the visualization of geotechnical failure processes such as the plastic collapse of a shallow foundation or the evolution of failure within a physical model landslide as it can yield full-field displacements at high spatial and temporal resolution. The adoption of digital image correlation methods by the geotechnical engineering community over the past 15 years has therefore provided researchers with a transformative tool for the visualization of failure mechanisms and the quantification of soil and soil–structure interaction behaviour within physical model experiments. The objective of this Canadian Geotechnical Colloquium is to provide an updated review of the factors that affect accuracy and precision of the technique and to highlight selected recent advances and emerging uses of DIC in geotechnical engineering applications with particular emphasis on geotechnical physical modelling and field monitoring.
42
Liao, Yi-Hong, Manzhu Xu, and Song Zhang. "Digital image correlation assisted absolute phase unwrapping." Optics Express 30, no. 18 (2022): 33022. http://dx.doi.org/10.1364/oe.470704.
Full textAbstract:
This paper presents an absolute phase unwrapping method for high-speed three-dimensional (3D) shape measurement. This method uses three phase-shifted patterns and one binary random pattern on a single-camera, single-projector structured light system. We calculate the wrapped phase from phase-shifted images and determine the coarse correspondence through the digital image correlation (DIC) between the captured binary random pattern of the object and the pre-captured binary random pattern of a flat surface. We then developed a computational framework to determine fringe order number pixel by pixel using the coarse correspondence information. Since only one additional pattern is used, the proposed method can be used for high-speed 3D shape measurement. Experimental results successfully demonstrated that the proposed method can achieve high-speed and high-quality measurement of complex scenes.
43
Ravanelli, R., A. Nascetti, M. Di Rita, et al. "A NEW DIGITAL IMAGE CORRELATION SOFTWARE FOR DISPLACEMENTS FIELD MEASUREMENT IN STRUCTURAL APPLICATIONS." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W2 (July 5, 2017): 139–45. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w2-139-2017.
Full textAbstract:
Recently, there has been a growing interest in studying non-contact techniques for strain and displacement measurement. Within photogrammetry, Digital Image Correlation (DIC) has received particular attention thanks to the recent advances in the field of lowcost, high resolution digital cameras, computer power and memory storage. DIC is indeed an optical technique able to measure full field displacements and strain by comparing digital images of the surface of a material sample at different stages of deformation and thus can play a major role in structural monitoring applications. <br><br> For all these reasons, a free and open source 2D DIC software, named py2DIC, was developed at the Geodesy and Geomatics Division of DICEA, University of Rome <q>La Sapienza</q>. Completely written in python, the software is based on the template matching method and computes the displacement and strain fields. The potentialities of Py2DIC were evaluated by processing the images captured during a tensile test performed in the Lab of Structural Engineering, where three different Glass Fiber Reinforced Polymer samples were subjected to a controlled tension by means of a universal testing machine. <br><br> The results, compared with the values independently measured by several strain gauges fixed on the samples, demonstrate the possibility to successfully characterize the deformation mechanism of the investigated material. Py2DIC is indeed able to highlight displacements at few microns level, in reasonable agreement with the reference, both in terms of displacements (again, at few microns in the average) and Poisson’s module.
44
Lin, Zhe, Tian Cai, and Yanfeng Wang. "Parallel reliability-guided algorithm for digital image correlation." Insight - Non-Destructive Testing and Condition Monitoring 61, no. 12 (2019): 729–37. http://dx.doi.org/10.1784/insi.2019.61.12.729.
Full textAbstract:
Digital image correlation is a non-contact optical method for measuring the displacement and strain on the surface of a material. The existing reliability-guided digital image correlation (RG-DIC) method is stable and reliable for a single image but it still needs a large calculational resource for a sequence of images. Due to the decorrelation effect, the reference image must be replaced several times to correct the measurement results for an image sequence involving a large deformation or a discontinuous deformation. Since the process must be executed sequentially, image by image, the total time required is often unacceptably large when the image sequence is long. The challenge is to find a way of improving the speed while retaining calculational reliability and measurement accuracy, which are important for the practical application of DIC. To address this problem, an improved method is proposed in this paper. The parallel bottleneck caused by the decorrelation effect is solved through improving the parallelism to increase the processing speed. This approach can be used to calculate the strain field of the surface of the material in cases of discontinuous deformation, such as in the area near to a crack. Compared with existing methods, this method not only retains the calculational reliability but also greatly improves calculation speed, especially on current multi-core computing platforms.
45
Coșa, Alexandra, Bogdan Hegheș, Camelia Negruțiu, and Zoltan Kiss. "Strain and Displacement Measurements in Reinforced Self-Compacting Concrete Beams with Openings Using Digital Image Correlation Technique." Proceedings 63, no. 1 (2020): 39. http://dx.doi.org/10.3390/proceedings2020063039.
Full textAbstract:
In structural engineering, strain and displacement are critical parameters, and measuring these parameters outside of the laboratory is a challenge for concrete researchers. Recent advances have enabled digital image correlation (DIC) to calculate the concrete surface displacements of chosen targets in a series of images recorded during an experiment. This paper presents a comparison between traditional and optical measurements to evaluate the efficiency of the DIC technique in recording the deformations of reinforced concrete beams. Tests were perfomed on two small-scale reinforced self-compacting concrete beams with small circular openings in 3-point bending.
46
Gao, Hong Li, Wei Jiang, Huan Liu, Huan Bin Zheng, and Hui Liu. "The Measurement of the Fatigue Crack-Tip Displacement and Strain Fields under High Frequency Resonant Loading Applying DIC Method." Applied Mechanics and Materials 710 (January 2015): 83–90. http://dx.doi.org/10.4028/www.scientific.net/amm.710.83.
Full textAbstract:
In order to measure the displacement and strain field in the fatigue crack tip area of CT specimens under high frequency resonant loading condition in the fatigue crack propagation test, a method based on the digital image correlation (DIC) and digital high-speed photography technology are proposed in this paper. First, a series of digital speckle images of CT specimen under sinusoidal alternating load were collected by digital high-speed photography equipment, the displacement and strain fields within the region of crack tip in each image were calculated by DIC. The sinusoidal changing strain curve has been obtained by the least square sine wave fitting method, and the characteristic parameters of sinusoidal strain are calculated, such as the amplitude, frequency, phase, mean load . The images of characteristic position in one stress cycle were obtained by comparing the fitted sine curve of strain with the corresponding speckle images. Finally, the dynamic strain gauge was used to measure the strain at crack tip point during one stress cycle, and the accuracy and feasibility of DIC method were verified by the experimental results. The study result presented in this paper will supply a foundation for exploring the crack propagation law and measuring the fatigue crack growth parameters under high frequency resonant loading condition further.
47
Tewari, Kavita, Rohit Gwalani, Preet Jain, Rishabh Sajin, Srishti Sharma, and Atharva Godse. "Deformation Analysis in Aluminium Magnesium Alloy Using Digital Image Correlation." SAMRIDDHI : A Journal of Physical Sciences, Engineering and Technology 14, no. 04 (2022): 105–9. http://dx.doi.org/10.18090/samriddhi.v14i04.16.
Full textAbstract:
Image processing is extensively used to examine surface deformations. Digital Image Correlation (DIC) detects two-dimensional subpixel displacements in two images to analyze deformations in geomechanical structures. In this study, the analysis is done on an aluminium-magnesium alloy. An optical microscope is used to capture the image, which is then processed and utilized to anticipate material deformation. To acquire findings of strain points on the material, the Ncorr application in the MATLAB environment is employed. . Strain graphs on the Exx, Exy, and Eyy axes, as well as U-displacement and V- displacement graphs, are generated to detect the deformation.
48
Pan, Bing, Hui Min Xie, Tao Hua, Wei Ning Wang, and Yan Fang. "Displacement Smoothing and Strain Estimation Using Savitaky-Golay Filters in Digital Image Correlation." Key Engineering Materials 326-328 (December 2006): 135–38. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.135.
Full textAbstract:
Recently, many research works were concentrated on how to improve the accuracy of displacement fields in digital image correlation (DIC). However, the original displacement fields calculated at discrete locations using DIC are unavoidably contaminated by noises. If the strain fields are directly computed by differentiating the original displacement fields, the noises will be amplified even at a higher level and the resulting strain fields are untrustworthy. To acquire reliably estimation of strain fields, in this paper, Savitaky-Golay (SG) filters are introduced to obtain smoothed displacement fields and reasonable strain estimation. The principle of two-dimensional SG filters is described in detail first. Then images of uniaxial tensile and three-point bending experiments were used to verify the proposed approach. The resulting smoothed displacement fields and strain fields clearly show that the proposed method is simple and effective.
49
Chen, Liang Chia, Ching Wen Liang, Huan Yu Tseng, and Shyh Tsong Lin. "Accurate 3-D Surface Profilometry Using Novel Boundary Edge Detection on Digital Image Correlation." Applied Mechanics and Materials 870 (September 2017): 295–302. http://dx.doi.org/10.4028/www.scientific.net/amm.870.295.
Full textAbstract:
A novel 3-D edge detection methodology is developed to resolve the edge ambiguity problem encountered in 3-D optical surface profilometry employing digital image correlation (DIC). DIC has been surged as a full-field measurement technique for in-plane and out-of-plane dynamic mechanical structure analyses. However, up to date, one of the key issues in DIC is still remained in boundary edge detection since a surface edge is not detectable between two discrete neighboring height jumps due to optical diffraction. Generally, it is common to observe undesirable noisy measured data along surface edges in traditional DIC-based surface 3-D profilometry. To resolve this, a novel random speckle images processing method is established by proposing a new algorithm by employing the multiple symmetric partial template model to determine best edge location with accurate height reconstruction. A theoretical simulation on a pre-calibrated circle target was performed to verify the feasibility of the methodology. Some experiments on real industrial objects having various surface reflective characteristics were implemented to verify its capability on accurate detection of industrial objects having discrete surface edges. From its preliminary evaluation on measurement accuracy, it is found that the maximum measured error on critical dimension can be controlled within less than 6.0% of the overall measuring range while one standard deviation can be kept within less than 1.2%.
50
Dematteis, Niccolò, and Daniele Giordan. "Comparison of Digital Image Correlation Methods and the Impact of Noise in Geoscience Applications." Remote Sensing 13, no. 2 (2021): 327. http://dx.doi.org/10.3390/rs13020327.
Full textAbstract:
Digital image correlation (DIC) is a commonly-adopted technique in geoscience and natural hazard studies to measure the surface deformation of various geophysical phenomena. In the last decades, several different correlation functions have been developed. Additionally, some authors have proposed applying DIC to other image representations, such as image gradients or orientation. Many works have shown the reliability of specific methods, but they have been rarely compared. In particular, a formal analysis of the impact of different sources of noise is missing. Using synthetic images, we analysed 15 different combinations of correlation functions and image representations and we investigated their performances with respect to the presence of 13 noise sources. Besides, we evaluated the influence of the size of the correlation template. We conducted the analysis also on terrestrial photographs of the Planpincieux Glacier (Italy) and Sentinel 2B images of the Bodélé Depression (Chad). We observed that frequency-based methods are in general less robust against noise, in particular against blurring and speckling, and they tend to underestimate the displacement value. Zero-mean normalised cross-correlation applied to image intensity showed high-quality results. However, it suffers variations of the shadow pattern. Finally, we developed an original similarity function (DOT) that proved to be quite resistant to every noise source.